CVE-2021-25220

MEDIUMNVD 6.88.6▲
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2022-03-24. NVD baseline CVSS 6.8; sources differ by 1.8.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 3%CVSS: 6.8Exploit: NoneExposed: 0

A fix is available — apply it.

BIND 9.11.0 -> 9.11.36 9.12.0 -> 9.16.26 9.17.0 -> 9.18.0 BIND Supported Preview Editions: 9.11.4-S1 -> 9.11.36-S1 9.16.8-S1 -> 9.16.26-S1 Versions of BIND 9 earlier than those shown - back to 9.1.0, including Supported Preview Editions - are also believed to be affected but have not been tested as they are EOL. The cache could become poisoned with incorrect records leading to queries being made to the wrong servers, which might also result in false information being returned to clients.

CVSS v3
6.8
EG Score
8.6(medium)
EPSS
87.3%
KEV
Not listed

Published

March 23, 2022

Last Modified

November 21, 2024

References (20)

Vendor Advisories for CVE-2021-25220(5)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(13)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntubind9-host (1:9.16.15-1ubuntu1.2) @ impish2026-05-26ubuntu
ubuntubind9-host (1:9.9.5.dfsg-3ubuntu0.19+esm6) @ trusty2026-05-26ubuntu
redhatbind-32:9.8.2-0.68.rc1.el6_10.172025-12-17redhat
redhatbind9.16-32:9.16.23-0.7.el8_6.92025-11-26redhat
redhatbind-32:9.16.23-1.el9_0.112025-11-20redhat
redhatbind-32:9.11.26-4.el8_4.82025-11-19redhat
redhatbind-32:9.11.13-6.el8_2.112025-11-19redhat
redhatdhcp-12:4.3.6-47.el8_6.22024-05-07redhat
redhatbind-32:9.11.4-26.P2.el7_9.132023-01-24redhat
redhatdhcp-12:4.4.2-17.b1.el92022-11-15redhat
redhatbind-32:9.16.23-5.el9_12022-11-15redhat
redhatbind9.16-32:9.16.23-0.9.el8.12022-11-08redhat
redhatbind-32:9.11.36-5.el82022-11-08redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(9)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 12× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 101 total refreshes for this CVE.

  1. 2026-07-22 14:06 UTCEPSS rescore
  2. 2026-07-22 14:06 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-20 17:05 UTCEPSS rescore
  6. 2026-07-19 14:28 UTCEPSS rescore
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  9. 2026-07-18 10:02 UTCEPSS rescore
  10. 2026-07-18 10:02 UTCEPSS rescore
  11. 2026-07-17 19:59 UTCOSV refresh
  12. 2026-07-16 17:00 UTCEPSS rescore
  13. 2026-07-15 16:55 UTCEPSS rescore
  14. 2026-07-15 16:55 UTCEPSS rescore
  15. 2026-07-15 01:58 UTCEPSS rescore
  16. 2026-07-13 22:27 UTCEPSS rescore
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  21. 2026-07-11 08:25 UTCEPSS rescore
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  23. 2026-07-09 19:07 UTCEPSS rescore
  24. 2026-07-08 15:12 UTCEPSS rescore
  25. 2026-07-07 13:43 UTCEPSS rescore
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  1. 2026-07-06 16:25 UTCEPSS rescore
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  3. 2026-07-06 02:21 UTCEPSS rescore
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  5. 2026-07-05 02:28 UTCEPSS rescore
  6. 2026-07-04 06:29 UTCEPSS rescore
  7. 2026-07-04 06:29 UTCEPSS rescore
  8. 2026-07-02 16:57 UTCEPSS rescore
  9. 2026-07-01 15:03 UTCEPSS rescore
  10. 2026-06-30 23:20 UTCEPSS rescore
  11. 2026-06-30 23:20 UTCEPSS rescore
  12. 2026-06-29 17:53 UTCOSV refresh
  13. 2026-06-29 14:04 UTCEPSS rescore
  14. 2026-06-28 14:05 UTCEPSS rescore
  15. 2026-06-28 04:54 UTCEPSS rescore
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  17. 2026-06-27 03:06 UTCEPSS rescore
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  19. 2026-06-25 13:48 UTCEPSS rescore
  20. 2026-06-25 13:48 UTCEPSS rescore
  21. 2026-06-24 14:03 UTCEPSS rescore
  22. 2026-06-24 14:03 UTCEPSS rescore
  23. 2026-06-23 21:31 UTCEPSS rescore
  24. 2026-06-23 21:31 UTCEPSS rescore
  25. 2026-06-22 14:24 UTCEPSS rescore
  26. 2026-06-22 14:24 UTCEPSS rescore
  27. 2026-06-21 14:55 UTCEPSS rescore
  28. 2026-06-21 14:54 UTCEPSS rescore
  29. 2026-06-21 01:58 UTCEPSS rescore
  30. 2026-06-21 01:58 UTCEPSS rescore
  31. 2026-06-19 19:24 UTCEPSS rescore
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  33. 2026-06-18 17:51 UTCEPSS rescore
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  35. 2026-06-17 17:51 UTCEPSS rescore
  36. 2026-06-16 17:51 UTCEPSS rescore
  37. 2026-06-15 17:46 UTCEPSS rescore
  38. 2026-06-14 23:15 UTCEPSS rescore
  39. 2026-06-13 22:58 UTCEPSS rescore
  40. 2026-06-13 22:58 UTCEPSS rescore
  41. 2026-06-12 23:10 UTCEPSS rescore
  42. 2026-06-12 06:36 UTCOSV refresh
  43. 2026-06-11 13:58 UTCEPSS rescore
  44. 2026-06-10 22:16 UTCEPSS rescore
  45. 2026-06-10 13:20 UTCEPSS rescore
  46. 2026-06-08 14:15 UTCEPSS rescore
  47. 2026-06-07 15:23 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-06 13:46 UTCEPSS rescore
  50. 2026-06-06 13:46 UTCEPSS rescore
  51. 2026-06-06 13:46 UTCEPSS rescore
  52. 2026-06-05 22:45 UTCEPSS rescore
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  54. 2026-06-05 06:09 UTCEPSS rescore
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  56. 2026-06-04 13:10 UTCEPSS rescore
  57. 2026-06-04 13:10 UTCEPSS rescore
  58. 2026-06-02 20:11 UTCEPSS rescore
  59. 2026-06-02 20:11 UTCEPSS rescore
  60. 2026-06-02 20:11 UTCEPSS rescore
  61. 2026-06-01 13:50 UTCEPSS rescore
  62. 2026-06-01 13:50 UTCEPSS rescore
  63. 2026-05-31 22:29 UTCEPSS rescore
  64. 2026-05-31 22:29 UTCEPSS rescore
  65. 2026-05-31 00:15 UTCEPSS rescore
  66. 2026-05-29 13:42 UTCEPSS rescore
  67. 2026-05-28 13:43 UTCEPSS rescore
  68. 2026-05-28 13:43 UTCEPSS rescore
  69. 2026-05-27 13:39 UTCEPSS rescore
  70. 2026-05-27 13:39 UTCEPSS rescore
  71. 2026-05-26 13:42 UTCEPSS rescore
  72. 2026-05-26 07:17 UTCEPSS rescore
  73. 2026-05-26 07:17 UTCEPSS rescore
  74. 2026-05-26 01:11 UTCEG score recompute
  75. 2026-05-26 01:11 UTCVendor advisory

Frequently asked(5)

What is CVE-2021-25220?
CVE-2021-25220 is a medium vulnerability published on March 23, 2022. BIND 9.11.0 -> 9.11.36 9.12.0 -> 9.16.26 9.17.0 -> 9.18.0 BIND Supported Preview Editions: 9.11.4-S1 -> 9.11.36-S1 9.16.8-S1 -> 9.16.26-S1 Versions of BIND 9 earlier than those shown - back to 9.1.0, including Supported Preview Editions - are also believed to be affected but have not been tested as…
When was CVE-2021-25220 disclosed?
CVE-2021-25220 was first published in the National Vulnerability Database on March 23, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-25220 actively exploited?
CVE-2021-25220 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 87.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-25220?
CVE-2021-25220 has a CVSS v3 base score of 6.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.6.
How do I remediate CVE-2021-25220?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-25220, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-25220

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